Bathtub



FIG. 1 is a top perspective view of a bathtub, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a side elevational view thereof, the opposite side being the same as the side shown; and

FIG. 4 is an end elevational view thereof the opposite end being the same as the end shown. 

The ornamental design for a bathtub, as shown and described. 